Commutator dresser



p 1965 E. HAUGLAND 3,204,498

COMMUTATOR DRESSER Filed May 15, 1962 54 FIE. 1

4 rrazuzys 3,204,498 COMMUTATOR DRESSER Earl Haugland, Hampden, N. Dak. Filed May 15, 1962, Ser. No. 194,881 3 Claims. ('Cl. 82-6) This invention relates generally to commutator dressers, and pertains more particularly to apparatus for dressing commutators in which a conventional electric drill can be employed as the driving or power means.

One object of the invention isto provide a commutator dresser in which an ordinary electric drill can be used for rotating the armature when turning down the commutator and thereafter utilized for supplying power when undercutting the insulation between commutator bars. The invention also has for an aim the provision of apparatus in which the changeover or progression from the turning step to the undercutting step can be quickly accomplished.

It is also an object of the invention to provide a fixture requiring but only a few parts. In this latter regard, it is within the contemplation of the invention to employ certain basic parts with respect to mounting the cutter when turning down the commutator and which basic parts, with but a slight substitution, can be employed when undertaking the undercutting operation. Thus, the invention makes it possible to provide a commutator dresser that can be made and sold at a relatively low price. 1

Yet another object is to provide apparatus of the foregoing character that is quite lightweight, although sturdy, so that it can be easily moved from place to place as circumstances dictate.

Quite briefly, the invention envisages a pivotal pulley mount to which the electric drill can be first connected for rotating the armature about its longitudinal axis through the intermediary of a flexible belt. During the rotation of the armature a cutting tool is positioned on a slidable mount for turning down the commutator. The same basic second mount employed in the turning process is then used for supporting the electric drill with a small rotary saw thereon. The drill is then moved longitudinal- ,ly by the same mechanism previously used to move the cutting tool in order to undercut the mica insulation between commutator bars, the armature being manually rotated through appropriate angular increments to permit this.

These and other objects and advantages of my invention will more fully appear from the following description, made in connection with the accompanying drawing, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a top plan view of a commutator dresser constructed in accordance with the teachings of the present invention when utilizing an electric drill to rotate the armature while turning down its commutator;

FIGURE 2 is a plan view of my apparatus when using the electric drill to undercut the insulation between two adjacent commutator bars;

FIGURE 3 is a view taken in the direction of line 3-3 of FIGURE 1 to show to better advantage the manner in which the cutting tool is mounted when turning down the commutator; and

FIGURE 4 is a view similar to FIGURE 3 but taken along line 4-4 of FIGURE 2.

Referring now in detail to the drawing, the commutator dresser there exemplifying the invention has been denoted in its entirety by the reference numeral 10. As illustrated,

the apparatus 10 comprises a bracket or supporting member 12 at the left to which a pair of parallel guide rods 14, 16 are secured, as by pins 18. At the right end is a fixed bearing plate 20, the plate 20 being attached to the rods by nuts 22 threaded onto the ends thereof. The sup- .United States Patent porting member 12, the guide rods 14, 16, and the bearing plate 20 constitute a base or frame on which are carried additional parts hereinafter described.

A second bearing plate 24 has its lower edge preferably spaced somewhat above the plane in which the bottom of the supporting member 12 and the bottom edge of the fixed bearing plate 20 reside, the plate 24 being easier adjusted this way. Integral with the plate 24 are sleeves 26 which slidably encircle the guide rods 14 and 16, each sleeve having a set screw 28 by which the plate 24 can be retained in an adjusted position. The plates 20 and 24 are provided with suitable bearing means at 30 and 32, respectively, for journaling an armature 34 having a commutator 36 which is to be dressed. The commutator, as is conventional, is comprised of a series of angularly spaced commutator bars 38, each being electrically separated by mica insulation 40. The shaft 42 of the armature 34 is rotatably supported in the bearing means 30 and 32, each of which bearing means is preferably of the construction illustrated in my copending application, Serial No. 171,749, filed February 7, 1962, for Portable Commutator Dressing Apparatus, now Patent No. 3,- 128,533.

Continuing with the description of the dressing apparatus 10, a pivotal mount 44 includes a member 46 drilled at its lower end, as indicated by the reference numeral 48, so as to freely encircle the guide rod 14. At its upper end is a bearing means 50, more specifically, a pillow block bearing, in which is journaled a shaft 52 extending parallel to the guide rod 14. Keyed to one end of the shaft 52 is a pulley 54, a flexible belt 56 passing about this pulley 54 and also about the armature 34 when turning down the commutator 36. The means for driving the pulley 54, and hence causing rotation of the armature 34 constitutes an electric power drill 58 having a conventional motor (not visible) contained within its casing 60. Also, as is conventional with electric power drills, there is a chuck 62 normally employed for gripping a drill bit, but which is used in this instance for gripping the shaft 52.

The apparatus 10 further comprises a slidable cutter mount 64 which includes a horizontal plate member 66 drilled at 68 and 70 so as to render the mount 64 readily slidable along the guide rods 14, 16. From FIGURE 3 it will be discerned that the mount 64 has as a part thereof an upstanding post 72.

Because we are at this time dealing with parts that are employed in turning down the commutator 36, the mount 64 in FIGURES 1 and 3 supports a cylindrical tool holder 74 having an axial recess 76 which fits over the post 72, a set screw 78 releasably retaining the tool holder 74 in place. At the appropriate height a diametrically extending aperture 80 of rectangular cross section is formed in the tool holder 74 for the accommodation of a cutting tool or hit 82. A set screw 84 anchors the tool 82 during the commutator turning down procedure.

For the purpose of shifting the mount 64 rectilinearly along the guide rods, an actuating rod 86 is employed, this actuating rod 86 being slidably supported by a sleeve bearing 88 on the bearing plate 20. A lever arm 90 having a handle 92 is pivotally connected to the rod 86 by means of a pin 94. An car 96 is fixedly disposed on the plate 20 and an intermediate link 98 is articulatively connected between the arm 90 and the ear 96 by two pins 100, 102.

One of the features of the present invention is to utilize the mount 64 during the undercutting step as well as durring the subsequent turning down step. Accordingly, attention is now directed to FIGURES 2 and 4 where the mount '64 has a cylindrical bearing support 104 attached thereto. The support 104 has an axial recess 106 corresponding in size to the recess 76 in the bottom of the tool holder 64 so as to permit the post 72 to be received therein.. A set screw 108 retains the support 104 in place.

At the upper end of the support 104 is a shaft 110 journaled for rotation by sleeve bearing means 112 which is appropriately retained within said support. The shaft 110 carries at one end a rotary disc saw 1140f the appropriate thickness to zfit between adjacent bars 38 of the commutator 36. The disc saw or blade 1 14 has a relatively small diameter, suggestively on the order of 7 inch, ro-accomplish the undercutting of the mica insulation 40 as far to the left as possible, that is, quite close to the conductors leading from the armature windings to the commutator 36. A fairly long screw 11-6, which is offset from. the sleeve bearing 1 1;2,,is th rea dedly carried by the support 104 so that its lower end bears against the top of the post 72.

Having in mind the foregoing construction, the manner of operating and using my commutator dresser should be readily understood. Initially the belt 56 is placed about the armature 64. The armature34 is then inserted into the apparatus and the bearing plate 24 moved so as to cause the bearing means 32 to engage the end of the shaft 42 adjacent thereto with the other end of the shaft 42 engaging the bearing means'SO.

If not done previously, the tool holder 74 is then, placed over the post 72 and the set screw 78 tightened. Through the medium of the set screw 84, the cutting tool 82 can be positioned radially tor. the proper depth of initial out when turning down the commutator 36.

Itcan now be appreciated that everything is in readiness for connecting the electric drill 5-8 to the shaft 52. This is done by means of thechuck 62. Due to the fact that the mount 44 is pivota llyrsup-ported on the guide-rod 14, the belt 56 can be easily tightened by merely manually urging the electric drill :58 away from the armature 34. Consequently, while holding the electric drill58 in ones left hand, the armature 34 can .be rotated.

concomitantly with the rotation of the armature, 34'by the electric drill 58, the user of my apparatus grasps the handle 92 to swing the lever arm '90-cl ockwise through an appropriate arc to move the cutter mount 64 longitudinally along'theguide rods 14, 1 6.- Such movement in turn causes the cutting tool 82 to traverse the commutator 3.6 and thereby cut downthe bars 38 as they rotate relative to the tool. The depth of out can be selected so as not to produce chattering of the tool 82, and by the same token a sufii-c'ient number of passes over the commutator. can be made to remove all pitting on-the bars 38.

After the commutator turning down step, asdescribed above, the toolholder: 74 is replaced with thebearing support 104, the screw 11 6 permitting the height of the rotary saw 114 to be positioned at the proper elevation for the undercutting step. The set screw 108, on the other hand, prevents the support 104 fromitwisting about a vertical axis.

The electric drill 58 isthen transposed from the positi-on inwhich it appears in FIGURE, 1 to the position shown in FIGURE 2. This iseasily done as-the chuck 162 can be loosened'to release the shaft 52 andthen retightened to grip the shaft 110 after the electric drill has been shifted.

With. the saw 114. being driven by the electric drill 58, as shown in FIGURES, 2 and 4, the undercutting of the mica insulation 40 is readily achieved, for thecutter mount 64 can. again bemoved longitudinally. along the guide rods 1.4, 16. When one strip of mica 4tlhas been undercut, thenthe armature 34 can bepartially rotated by hand to present the next strip to the saw 114 and so on.

After the undercutting step. has been completed, the bearing plate 24 can be backed away from the shat42 by loosening the screws 28 and the apparatus is then ready for another armature,

It will, of course, be understood that various changes may be made in the form, details, arrangementaand pro- 4 portions of the parts without departing from the scope of my invention as set forth in the appended claims.

What is claimed is:

1. Commutator dressing apparatus comprising:

(a) afirst bearing plate;

(b) a pair of guide rods of equal length anchored at one endto said bearing plate;

(0) means for fixedly supporting the other ends of said guide rods to maintain said rods in a spaced, parallel relation;

((1) a second bearing plate slidably carried on said guide rods, said second bearing plate having a pair of laterally spaced sleeves fixedly secured thereto and freely encircling said guide rods so that said second-bearing plate can be longitudinally positioned at difierent locations along said guide rods relative said first bearing plate;

(e) a pivotal pulley mount slidably supported on one of said guide rods between said bearing plates, said pulley mount including a shaft having a pulley at one end and its other end for gripping by the chuck of an-electric drill;

(:f) a flexible belt engageable with said pulley and adapted to encircle an armature when journaled for rotation between said bearing plates;

(g) a cutter mount slidahle on said guide rods;

(h) means for actuating said cutter mount;

(i) a tool holder adapted to be attached to said cutter mount;

(j) abearing support adapted to be attached to said cutter mount, said bearing support having a rotatable shaft provided with a rotary saw blade at one end and having its other end receivable in the chuck of saidelectric drill, and

(k) a set screw extending through each sleeve for maintaining said second bearing plate in a selected position with respect to said first bearing plate.

2. Commutator dressing apparatus comprising:

' (a) a first bearing plate;

(b) a pair of guide rods anchored at one end to said bearing plate;

(c) means for supporting the other ends of said guide rods;

(d) a second bearing plate slidably carried on said guide rods;

(e) a pivotal pulley mount slidably supported on one of said guide rods, said pulley mount including a shaft having a pulley at one end and its other end for gripping by the chuck of an electric drill;

(f) a flexible belt engageable with said pulley and adapted to encircle an armature when journalcd for rotation between said bearing plates;

(g) a cutter mount slidable on said guide rods, said cutter mount being provided with an upstanding post;

(h) means for actuating said cutter mount;

(i) a tool holder adapted to be attached to said cutter mount, and

(j) a bearing support adapted to be attached to said cutter mount, said bearing support having a rotatable shaft provided with a rotary saw blade at one end and having its other end receivable in the, chuck of said electric .drill,

(k) said tool holder and said bearing support each being provided with an axial recess having a cross section such as to fit .over said post.

3. Commutator dressing apparatus in accordance with claim 2 in which:

(a) said bearing support is provided with a vertically disposed screw having its lower end engageable with the upper end of said post for raising and lowering said bearing support.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS 12/30 Miller 2927 .2

11/36 Green 2927.2 5

1/ 39 Mansfield 82-4 X 8/39 Jackson 8236 6 2,303,106 11/42 Bourhenn 8234 X 2,733,741 2/ 5 6 Lindee 825 X FOREIGN PATENTS 46,511 4/ 3 6 France.

(1st addition to No. 777,610)

WILLIAM W. DYER, .TR., Primary Examiner. 

1. COMMUTATOR DRESSING APPARATUS COMPRISING: (A) A FIRST BEARING PLATE; (B) A PAIR OF GUIDE RODS OF EQUAL LENGTH ANCHORED AT ONE END OF SAID BEARING PLATE; (C) MEANS FOR FIXEDLY SUPPORTING THE OTHER ENDS OF SAID GUIDE RODS TO MAINTAIN SAID RODS IN A SPACED, PARALLEL RELTION; (D) A SECOND BEARING PLATE SLIDABLY CARRIED ON SAID GUIDE RODS, SAID SECOND BEARING PLATE HAVING A PAIR OF LATERALLY SPACED SLEEVES FIXEDLY SECURED THERETO AND FREELY ENCIRCLING SAID GUIDE RODS SO THAT SAID SECOND BEARING PLATE CAN BE LONGITUDINALLY POSITIONED AT DIFFERENT LOCATIONS ALONG SAID GUIDE RODS RELATIVE SAID FIRST BEARING PLATE; (E) A PIVOTALLY PULLEY MOUNT SLIDABLY SUPPORTED ON ONE OF SAID GUIDE RODS BETWEEN SAID BEARING PLATES, SAID PULLEY MOUNT INCLUDING A SHAFT HAVING A PULLEY AT ONE END AND ITS OTHER END FOR GRIPPING BY THE CHUCK OF AN ELECTRIC DRILL; (F) A FLEXIBLE BELT ENGAGEABLE WITH SAID PULLEY AND ADAPTED TO ENCIRCLE AN ARMATURE WHEN JOURNALED FOR ROTATION BETWEEN SAID BEARING PLATES; (G) A CUTTER MOUNT SLIDABLE ON SAID GUIDE RODS; (H) MEANS FOR ACTUATING SAID CUTTER MOUNT; (I) A TOOL HOLDER ADAPTED TO BE ATTACHED TO SAID CUTTER MOUNT; (J) A BEARING SUPPORT ADAPTED TO BE ATTACHED TO SAID CUTTER MOUNT, SAID BEARING SUPPORT HAVING A ROTATABLE SHAFT PROVIDED WITH A ROTARY SAW BLADE AT ONE END AND HAVING ITS OTHER END RECEIVABLE IN THE CHUCK OF SAID ELECTRIC DRILL, AND (K) A SET SCREW EXTENDING THROUGH EACH SLEEVE FOR MAINTAINING SAID SECOND BEARING PLATE IN A SELECTED POSITION WITH RESPECT TO SAID FIRST BEARING PLATE. 